FUEL SYSTEM LAYOUT STRUCTURE IN MOTORCYCLE

Abstract

[Object] In a motorcycle in which a fuel pump attached to an upper wall of a fuel tank mounted on a vehicle body frame is contained in the fuel tank and the upper side of the fuel tank is covered with a riding seat, to prevent the riding seat from interfering with a connection portion for connection to the fuel pump, while increasing the degree of freedom in setting the height of the riding seat. [Solving Means] A fuel pump 118 is mounted to a pump mount portion 119 provided in an upper wall of a fuel tank 34 in the state of being recessed downwards, and the pump mount portion 119 is covered with a cover 138 from the upper side.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970]
COMPLETE SPECIFICATION
[See Section 10, rule 13]
"FUEL SYSTEM LAYOUT STRUCTURE IN MOTORCYCLE"
HONDA MOTOR CO., LTD., a corporation of Japan, of 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan,
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:-

[Detailed Description of the Invention] [0001] [Technical Field to which the Invention Pertains]
The present invention relates to a motorcycle in which a fuel pump mounted to an upper wall of a fuel tank mounted on a vehicle body frame is contained in the fuel tank and the upper side of the fuel tank is covered with a riding seat, and particularly to an improvement in a fuel system layout structure in a motorcycle. [0002] [Prior Art]
A motorcycle in which the upper side of a fuel tank containing a fuel pump therein is covered with a riding seat has already been known, for example, in Patent
2

Reference 1 and the like.
[0003]
[Patent Reference 1]
Japanese Patent Publication No. Hei 7-110630
[0004]
[Problems to be Solved by the Invention]
Meanwhile, in a structure in which a fuel tank is mounted to an upper wall of a fuel tank, a connection portion between the fuel pump and a fuel hose is disposed on the upper wall of the fuel tank, and it is necessary to avoid interference of a riding seat with the connection portion. In the above-mentioned conventional structure, the height of the riding seat is set at such a position as not cause interference with the connection portion, with the result that the degree of freedom in setting the height of the riding seat is narrowed.
[0005]
The present invention has been made in consideration of the foregoing. Accordingly, it is an object of the present invention to provide a fuel system layout structure in a motorcycle with which it is possible to prevent a riding seat from interfering with a connection portion for connection to a fuel pump, while increasing the degree of freedom in setting the height of

the riding seat.
[0006]
[Means for Solving the Problems]
In order to attain the above object, the invention as set forth in claim 1 is characterized in that, in a motorcycle including a fuel tank mounted on a vehicle body frame, and a fuel pump mounted to an upper wall of the fuel tank, the fuel pump being contained in the fuel tank, and the upper side of the fuel tank being covered with a riding seat, the fuel pump is mounted to a pump mount portion provided in the upper wall of the fuel tank in the state of being recessed downwards, and the pump mount portion is covered with a cover from the upper side.
[0007]
According to such a constitution of the invention of claim 1, the pump mount portion to which to mount the fuel pump is provided in the upper wall of the fuel tank in the state of being recessed downwards. Therefore, even though a connection portion for connection to the fuel pump is disposed on the pump mount portion, it is possible to avoid interference thereof with the riding seat, and to increase the degree of freedom in setting the height of the riding seat. Moreover, since the upper side of the pump mount portion is covered with the cover

from the upper side, it is possible to securely prevent erroneous contact with the connection portion at the time when the riding seat is opened for supplying a fuel into the fuel tank or the like purpose, and to protect the connection portion for connection to the fuel pump. Besides, it is possible to prevent the connection portion from being exposed, and to obtain ari excellent appearance.
[0008]
In addition, the invention as set forth in claim 2 is charachterized, in addition to the constitution. of the invention of claim 1, in that the pump mount portion is provided with an insertion hole for inserting the fuel pump into the fuel tank, a lid plate provided at the upper end of the fuel pump is attached to the pump mount portion so as to close the insertion hole from the upper side, and the cover is attached to the lid plate. According to such a constitution, it is possible to eliminate the need for a special member for fixing the cover to the fuel tank side, and thereby to contrive a reduction in the number of component parts.
[0009]
The invention as set forth in claim 3 is characterized, in addition to the constitution of the invention as set forth in claim 1 or 2, in that at a

position spaced from the fuel pump, the cover is attached to a stay provided on the vehicle body frame in the state of supporting the fuel tank. According to such a constitution, it is possible to eliminate the need for a component part for exclusive use for attaching the cover, thereby to contrive a reduction in the number of component parts, and to firmly support the cover. [0010]
The invention as set forth in claim 4 is characterized, in addition to the constitution of the invention as set forth in any of claims 1 to 3, in that a luggage box covered with the riding seat is disposed on the front side of the fuel tank disposed on the upper side of a rear wheel, the pump mount portion and the fuel pump are disposed at a front portion on one of the left and right sides of the fuel tank, either a front end portion on the other of the left and right sides of the fuel tank or a rear end portion on the other of the left and right sides of the luggage box is provided with a cutout for passing hoses extended from the fuel pump side into a space between a front portion of the fuel tank and a rear portion of the luggage box, and the hoses are disposed in the state of being bent in a roughly U-shaped form opened on one side in the left-right direction on
6

the rear side of the luggage box. [0011]
According to such a constitution of the invention of claim 4, it is possible to dispose the fuel pump at a deep position in the fuel tank, and to smoothly lay out the hoses. Namely, while a central portion in the left-right direction of the fuel tank is made shallow due to the arrangement of the fuel tank on the upper side of the rear wheel, the arrangement of the fuel pump on one of the left and right sides of the fuel tank makes it possible to dispose the fuel pump at a deep position in the fuel tank. In addition, the hoses extended from the fuel pump are passed through the cutout provided in either the front end portion on the other of the left and right sides of the fuel tank or the rear end portion on the other of the left and right sides of the luggage box, and are disposed in the state of being bent in the roughly U-shaped form. Therefore, notwithstanding the presence of the luggage box on the front side of the fuel tank, it is possible to cause the hoses to be moderately bent instead of being sharply bent, and to smoothly lay out the hoses. [0012]
Furthermore, the invention as set forth in claim 5

is characterized, in addition to the constitution of the invention as set forth in any of claims 1 to 4, in that seat load receiving positions for making it possible to receive the riding seat are set on the upper wall of the fuel tank at a plurality of locations in the periphery of the pump mount portion. According to such a constitution, even when the riding seat sinks under the action of a large load, it is possible to receive the load of the riding seat by the upper wall of the fuel tank at the plurality of locations in the periphery of the pump mount portion. Therefore, it is possible to restrain deformation of the riding seat, and to prevent the load from the riding seat side from acting on the cover.
[0013]
[Mode for Carrying out the Invention]
Now, a mode for carrying out the present invention will be described below, based on embodiments of the invention shown in the accompanying drawings.
8

[Brief Description of the Drawings] [Fig. 1]
Fig. 1 is an overall side view of a motorcycle according to a first embodiment. [Fig. 2]
Fig. 2 is a perspective view of a central portion in the front-rear direction of the motorcycle in the condition where a vehicle body cover is removed. [Fig. 3]
Fig. 3 is a side view of an engine and an intake system. [Fig. 4]
Fig. 4 is an enlarged sectional view taken along line 4-4 of Fig. 3. [Fig. 5]
Fig. 5 is an enlarged view taken along arrow 5 of Fig. 3. [Fig. 6]
Fig. 6 is a sectional view taken along line 6-6 of Fig. 5. [Fig. 7]
Fig. 7 is a back elevation of an air cleaner taken
9

along arrow 7 of Fig. 3. [Fig. 8]
Fig. 8 is a sectional view taken along line 8-8 of Fig. 7. [Fig. 9]
Fig. 9 is a view taken along arrow 9 of Fig. 3. [Fig. 10]
Fig. 10 is a plan view of an intake pipe and a fuel injection valve. [Fig. 11]
Fig. 11 is a sectional view taken along line 11-11 of Fig. 10. [Fig. 12]
Fig. 12 is a vertically sectional side view of a rear portion of the motorcycle. [Fig. 13]
Fig. 13 is a sectional view taken along line 13-13 of Fig. 12. [Fig. 14]
Fig. 14 is a sectional view taken along line 14-14
of "Fig. 13. [Fig. 15]
Fig. 15 is an exploded perspective view of a fuel tank, a fuel pump and a cover.

[Fig. 16]
Fig. 16 is an enlarged sectional view taken along line 16-16 of Fig. 13. [Fig. 17]
Fig. 17 is a sectional view taken along line 17-17 of Fig. 16. [Fig. 18]
Fig. 18 is an enlarged sectional view taken along line 18-18 of Fig. 13. [Fig. 19]
Fig. 19 is a sectional view, corresponding to Fig. 13, of a second embodiment. [Fig. 20]
Fig- 20 is a plan view of a fuel tank and a luggage box in a third embodiment.
11

Figs. 1 to 18 illustrate an embodiment of the present invention, wherein Fig. 1 is an overall side view of a motorcycle; Fig. 2 is a perspective view of a central portion in the front-rear direction of the motorcycle in the condition where a vehicle body cover is
12

removed; Fig. 3 is a side view of an engine and an intake system; Fig. 4 is an enlarged sectional view taken along line 4-4 of Fig. 3; Fig. 5 is an enlarged view taken along arrow 5 of Fig. 3; Fig. 6 is a sectional view taken along line 6-6 of Fig. 5; Fig. 7 is a back elevation of an air cleaner taken along arrow 7 of Fig. 3; Fig. 8 is a sectional view taken along line 8-8 of Fig. 7; Fig. 9 is a view taken along arrow 7 of Fig. 3; Fig. 10 is a plan view of an intake pipe and a fuel injection valve; Fig. 11 is a sectional view taken along line 11-11 of Fig. 10; Fig. 12 is a vertically sectional side view of a rear portion of the motorcycle; Fig. 13 is a sectional view taken along line 13-13 of Fig. 12; Fig. 14 is a sectional view taken along line 14-14 of Fig. 13; Fig. 15 is an exploded perspective view of a fuel tank, a fuel pump and a cover; Fig. 16 is an enlarged sectional view taken along line 16-16 of Fig. 13; Fig. 17 is a sectional view taken along line 17-17 of Fig. 16; and Fig. 18 is an enlarged sectional view taken along line 18-18 of Fig. 13. [0015]
First, in Fig. 1, a vehicle body frame 20 of this motorcycle comprises a head pipe 21 for steerably bearing a front fork 24, a main frame 22 extending rearwardly downwards from the head pipe 21, and a left-right pair of

rear frames 23--- provided in connection with a rear portion of the main frame 22 and extending rearwardly upwards. A front wheel WF is shaft-supported at the lower ends of the front fork 24, a bar-like steering handle 25 is connected to an upper portion of the front fork 24, and a front fender 26 for covering the upper side of the front wheel WF is supported on the front fork 24. [0016]
Referring to Figs. 2 and 3 also, the main frame 22 is composed of an angular pipe which is tetragonal in
cross-section, hanger plates 27--- are attached respectively to both side surfaces of an intermediate portion of the main frame 22, and pivot plates 28 are attached to both side surfaces of a rear portion of the main frame 22.
[0017]
An engine E with a cylinder axis set slightly forwardly upwards, for example, is disposed on the lower side of the main frame 22. The engine E is suspended from the vehicle body frame 20 so as to be supported by the hanger plate 27... and the pivot plates 28.
[0018]
A front end portion of a rear fork 29 is rockably borne on the pivot plates 28, and a rear wheel WR is

shaft-supported on the rear ends of the rear fork 29. Besides, a rear cushion 30 is provided between the rear
frames 23... of the vehicle body frame 20 and the rear fork 29.
[0019]
The engine E constitutes a power unit P together with a transmission M, and the output of the transmission M is transmitted to the rear wheel WR through a chain 31.
[0020]
In addition, a throttle body 3 2 and an air cleaner 33 on the front side relative to the throttle body 32 are disposed on the upper side of the engine E, and a fuel tank 34A is disposed on the upper side of the rear wheel WR. The upper side of a luggage box 3 5A, which is disposed on the front side of the fuel tank 34A, and the fuel tank 34A is openably and closably covered with a riding seat 36, which is, for example, of a tandem type.
[0021]
A synthetic resin-made vehicle body cover 38 for covering the vehicle body frame 20, a part of the engine E, the throttle body 32, the air cleaner 33, the fuel tank 34A and the luggage box 35A is attached to the vehicle body frame 20. The vehicle body cover 38 is comprised of front side covers 39... disposed on the left

and right sides of the main frame 22; leg shields 40... provided in connection with front portions of both the front side covers 39... so as to cover leg portions of the rider from the front side; a front top cover 41 provided in connection with both the leg shields 40--- so as to cover the head pipe 21 from the front side; a main frame top cover 42 provided in connection with the front top cover 41 so as to cover the head pipe 21 from the rear side and to cover the main frame 22 from the upper side; under covers 43... provided in connection with lower portions of both the front side covers 39... and rear side covers 44 for covering the fuel tank 34A and the luggage box 35A from both lateral sides.
[0022]
The riding seat 36 is disposed at upper portions of the rear side covers 44 in an openable and closable condition so as to enable the containing and taking-out of luggage into and out of the luggage box 3 5A and supply of a fuel into the fuel tank 34A, and a rear fender 45 for covering the upper side of a re&r portion of the rear wheel WR is provided in connection with the rear side covers 44.
[0023]
In Fig. 4, the throttle body 32 has a structure in

which a butterfly-type throttle valve 46 for regulating the amount of air supplied to the engine E is turnably borne on a body 47, and a throttle wire 4 9 is wrapped around and connected to a throttle drum 48 disposed on a lateral side of the body 47 in connection with the throttle valve 46. [0024]
The body 47 has an intake path 50 extending in the front-rear direction of the motorcycle, and the throttle valve 4 6 disposed in an intermediate portion of the intake path 50 is fixed to a valve shaft 51 turnably borne on the body 47 so as to cross the intake path 50. In addition, the throttle drum 48 is disposed on the left side of the body 47 in the state of being directed forwards in the running direction of the motorcycle, and the throttle drum 4 8 is fixed to one end of the valve shaft 51. Moreover, a return spring 52 for biasing the throttle valve 46 toward the closing side is provided between the throttle drum 48 and the body 47, and the throttle valve 46 is driven to turn to the opening side when the rider on the motorcycle pulls the throttle wire 49 against the spring force of the return spring 52.
[0025]
A housing 55 for housing the control unit 53 is
17

attached to a side surface opposite to the throttle drum 48, namely a right side surface, of the body 47. The housing 55 is comprised of a housing main body 56 attached to the body 47, and a lid plate 57 for hermetically closing an opening portion of the housing main body 56. The control unit 53 comprises an electronic circuit (not shown) fabricated on a circuit substrate 54 clamped between the housing main body 56 and the lid plate 57. [0026]
A throttle sensor 58 for detecting the opening of the throttle valve 46 is connected to the circuit substrate 54. The throttle sensor 58 is comprised of a rotor 59 rotatably loosely fitted in the housing main body 56, conductive brushes 60, 60 projected from the rotor 59 toward the side of the circuit substrate 54, and resistors 61 printed on the circuit substrate 54 so as to bring the conductive brushes 60, 60 into sliding contact therewith. The rotor 59 is chatterlessly fitted to the other end of the valve shaft 51 in such a manner that relative rotation is impossible. The rotor 59 is rotatably borne on a support shaft 62 which is projected on the lid plate 57 and is penetrating through the circuit substrate 54 coaxially with the valve shaft 51.

With such a throttle sensor 58, the opening of the throttle valve 46 is detected on the side of the control unit 53 as a voltage between both ends of the resistor 61. [0027]
In addition, the body 47 is provided with a through-hole 63 opened into the intake path 50, on the upstream side relative to the throttle valve 46. A detection cylinder 64, which has a thin bottomed cylindrical shape and which penetrates through the through-hole 63 with its tip end closed portion fronting on the intake path 50, is provided as one body with the housing main body 56. [0028]
An intake gas temperature sensor 67 is comprised of a thermistor 65 in close contact with the inside surface of the tip end closed portion of the detection cylinder 64, and a terminal 66 extending from the thermistor 65 inside the detection cylinder 64 and connected to the circuit substrate 54. The control unit 53 is so designed as to detect a voltage variation according to a variation in the resistance of the thermistor 65 attendant on a variation in intake gas temperature. Moreover, after the intake gas temperature sensor 67 is contained in the detection cylinder 64, the detection cylinder 64 is

filled with a potting agent 68 consisting of a synthetic resin.
[0029]
Thus, the throttle sensor 58 and the intake gas temperature sensor 67 are connected to the circuit substrate 54 of the control unit 53 attached to the throttle body 47, and, therefore, it is possible to make extremely short the wirings for connecting the throttle sensor 58 and the intake gas temperature sensor 61 to the control unit 53. [0030]
An upper portion of the housing 55 is extended astride an upper portion of the body 47 to the side of the throttle drum 48, and a coupler 69 opened to the same side as the throttle drum 48 is formed as one body with the housing main body 56 of the housing 55. [0031]
Paying attention to Fig. 3, a synthetic resin-made cleaner case 70 possessed by the air cleaner 33 is comprised of a bowl-shaped case main body 71 supported by the main frame 22, and a bowl-shaped cover 72 opened oppositely to the case main body 71, which are coupled to each other with a filter unit 73 clamped between peripheral portions thereof. The inside of the cleaner

case 70 is partitioned into an unclean chamber 74 on the side of the cover 12 and a clean chamber 75 on the side of the case main body 71. [0032]
A connecting tube 76 for leading cleaned air from the air cleaner 33 to the throttle body 32 is fixedly connected to the case main body 71 of the cleaner case 70 so that the upstream end of the connecting tube 76 projects into the clean chamber 75. An upstream-side connection cylinder 47a {see Fig. 4) provided as one body with the body 47 of the throttle body 32 is fitted to a downstream end portion of the connecting tube 76. Moreover, a fixing band 77 for fixingly maintaining a connection condition of the connecting tube 76 to the throttle body 32 is wound around the downstream end portion of the connecting tube 76. With the fixing band 77 fastened by a screw member 78, the connection condition of the connecting tube 76 to the throttle body 32 is fixedly maintained. [0033]
Referring to Figs. 5 to 8 also, a shield plate 79 for covering from the front side at least the throttle drum 48 of the throttle body 32 disposed on the rear lower side of the air cleaner 33 is provided by integral

molding with a lower portion of the case main body 71 in the cleaner case 70 of the air cleaner 33, and the coupler 69 possessed by the housing 55 in the throttle body 32 is also disposed on the side of the throttle drum 48, so that the coupler 69 is also covered with the shield plate 79 from the front side. [0034]
The shield plate 79 is provided with an operating opening portion 80, for example circular in shape, at a position corresponding to the fixing band 77. A lid 81 disposed on the front side of the shield plate 79 for making the operating opening portion 80 openable and closable is attached to the shield plate 79. [0035]
The shield plate 79 is provided with a support hole 82 at a position away from the operating opening portion 80. A support shaft 83 to be passed through the support hole 82 is integrally projected on the lid 81, which is formed of rubber, so that the diameter on the tip end side thereof can be reduced at the time of passing through the support hole 82. The support shaft 83 is integrally provided at its tip end with a plurality of engaging pawls 83a.. for springy engagement with the back surface of the shield plate 79 in the periphery of the

support hole 82. Namely, the lid 81 is attached to the shield plate 79 so as to be turnabls around the axis of the support hole 82, between a position for closing the operating opening portion 80 as indicated by solid line in Fig. 5 and a position for opening the operating opening portion 80 as indicated by chain line in Fig. 5.
[0036]
In addition, the lid 81 is integrally provided with a projected fitting cylinder 84 divided into a plurality of portions in the circumferential direction so as to be springily fitted in the operating opening portion 80 in the condition where the operating opening portion 80 is closed. A plurality of engaging pawls 84a--- provided at the tip end of the fitting cylinder 84 are springily engaged with the back surface of the shield plate 79 in the periphery of the operating opening portion 80, whereby the closed condition of the operating opening portion 80 closed with the lid 81 is maintained.
[0037]
The shield plate 79 is provided at its lower end, and at a portion corresponding to the head cover 87 of the engine E, with a cutout 79a for inserting a tool 86 such as a wrench into the head cover 87 at the time of performing, for example, adjustment of a tappet of a

valve-operating system in the engine E by detaching the head cover 87.
[0038]
In addition, a synthetic resin-made throttle drum guard 161 for covering the throttle drum 48 of the throttle body 32 from a lateral side, in this embodiment from the left side, is attached to the air cleaner 33. Specifically, a mount boss 71a for fastening an upper portion of the throttle drum guard 161 with a screw member 162 is integrally provided on the left side of the back surface of the case main body 71 in the cleaner case 70 of the air cleaner 33, and the shield plate 79 is provided in its left lower portion with a rectangular engaging hole 163 for engaging a roughly L-shaped engaging pawl 16la provided at a lower portion of the throttle drum guard 161.
[0039]
An upper portion of the throttle drum guard 161 having its lower portion in contact with the back surface of the shield plate 79 is fastened to the mount boss 71a with the screw member 162, while engaging the engaging pawl 161a in the engaging hole 163, whereby the throttle drum guard 161 is mounted to the air cleaner 33.
[0040]

In addition, an exhaust pipe 164 connected to an exhaust port (not shown) in the cylinder head 88 of the engine E is connected to a lower portion of the cylinder head 88, the downstream end of a pipe 165 for supplying fresh secondary air into an exhaust gas flowing through the exhaust port into the exhaust pipe 164 is connected to the head cover 87, and the upstream end of the pipe 165 is connected to a secondary air control valve 166 supported by the engine E. Besides, the secondary air control valve 166 is connected to a filter 167 supported by the main frame 22. [0041]
The downstream end of an air supply tube 16 8 extending forwards from the filter 167 along the main frame 22 is connected to the filter 167, and the upstream end of the air supply tube 16 8 extends to the upper side of the cover air cleaner 33 to be exposed, inside the vehicle body cover 38, to the atmosphere. [0042]
Moreover, the back surface of the case main body 71 in the cleaner case 70 of the air cleaner 33 is provided in its upper portion with a fitting groove 169 for fitting a portion near the upstream end of the air supply tube 168 therein, and an engaging pin 170 for making

contact with and engaging with the air supply tube 168 at the portion fitted in the fitting groove 169 from the upper side is integrally projected on the upper portion of the back surface. Namely, the portion near the upstream end of the air supply tube 168 is fitted in the fitting groove 169 and the engaging pin 170 is brought into contact and engagement therewith from the upper side, whereby the portion near the upstream end is maintained on the upper portion of the back surface of the case main body 71. Therefore, it is unnecessary to attach a clamper for exclusive use for maintaining the air supply tube 168 to the main frame 22. [0043]
A downstream-side connection cylinder 47b (see Fig. 4) integrally possessed by the body 47 of the throttle body 32 is connected to the upstream end of an intake pipe 89 the downstream end of which is connected to an upper portion of the cylinder head 88 in the engine E.
[0044]
Referring to Figs. 9 to 11 also, the intake pipe 89 is bent in a roughly C-shaped form so as to connect the throttle body 32 and the cylinder head 88 disposed on the rear lower side of the throttle body 32 to each other. The intake pipe 89 is covered with a rubber-made covering

member 90 in the manner of baking onto the surface thereof, and the downstream-side connection cylinder 47b of the throttle body 32 is tightly fitted in a connection cylinder member 90a provided as one body with the covering member 90, whereby the throttle body 32 is connected to the intake pipe 89.
[0045]
A fuel injection valve 91 for injecting a fuel into the cylinder head 88 is attached to the intake pipe 89, and the opening and olosinq operations of the fuel injection valve 91 are controlled by the control unit 53 contained in and fixed to the housing 55 mounted to the body 47 of the throttle body 32.
[0046]
The intake pipe 89 is provided with a mount hole 92 opened toward the side of the cylinder head 88, and a tip end portion of the fuel injection valve 91 is gas-tightly fitted in the mount hole 92 so that its tip end fronts on the inside of the intake pipe 89. In addition, a rear end portion of the fuel injection valve 91 is liquid-tightly fitted in a cap 93, and the cap 93 is fastened to the intake pipe 89. Namely, the fuel injection valve 91 is mounted to the intake pipe 89 in the manner of being clamped between the intake pipe 89 a.nd the cap 93.

[0047]
The cap 93 is provided with a fuel supply passage 94 having its downstream end communicated with the inside of a rear end portion of the fuel injection valve 91, and an inlet-side connection pipe 95 communicated with the upstream end of the fuel supply passage 94 is flange-connected to the cap 93.
[0048]
The cap 93 is provided with a return passage 96 branched from an intermediate portion of the fuel supply passage 94, and a pressure regulating valve 97 is connected to the return passage 96.
[0049]
A valve housing 98 of the pressure regulating valve 97 is disposed in parallel to the fuel injection valve 91 at a position adjacent to the fuel injection valve 91, and an upstream end portion of the valve housing 98 is attached to the cap 93, with a connection pipe 99 liquid-tightly communicated with the return passage 96 being interposed between the upstream end portion and the cap 93. Namely, the pressure regulating valve 97 is disposed to extend downwards from the cap 93 so that it does not project sideways from the cap 93.
[0050]

In addition, a cover 101 is connected to a lower portion of the valve housing 98, with a peripheral portion of a diaphragm 100 clamped between the cover 101 and the valve housing 98. A valve chamber 102 communicated with the return passage 96 is formed between the valve housing 98 and the diaphragm 100, and a spring chamber 103 is formed between the diaphragm 100 and the cover 101. [0051]
Besides, the valve housing 98 is integrally-provided with a return-side connection pipe portion 104 extending to the same side as the inlet connection pipe 95 flange-connected to the cap 93 on the lower side of the inlet connection pipe 95. A cylindrical valve seat member 105 communicated with the return-side connection pipe portion 104 is fitted and attached so as to front on a central portion of the valve chamber 102 and to have a part thereof projecting to the side of the diaphragm 100. A valve element 106 capable of being seated on an end portion, on the side of the valve chamber 102, of the valve seat member 105 is slightly rockably held on a central portion of the diaphragm 100, and a spring 107 disposed in a compressed state between the cover 101 and the diaphragm 100 is contained in the spring chamber 103

so as to exert a spring force toward the side for bending the diaphragm 100 to the side of the valve chamber 102. [0052]
In the pressure regulating valve 97 as above-described, when the liquid pressure on the side of the valve chamber 102 for biasing the diaphragm 100 toward the side of the spring chamber 103 exceeds the spring force on the side of the spring chamber 103 for biasing the diaphragm 100 toward the side of the valve chamber 102, the diaphragm 100 is bent to the side of the spring chamber 103, the valve element 106 parts from the valve seat member 105, and the liquid pressure in the fuel supply passage 94 communicated to the valve chamber 102 through the return passage 106, i.e., the pressure of supply of the fuel to the fuel injection valve 91, is so regulated as not to reach or exceed a set pressure. [0053]
In addition, since the pressure regulating valve 97 is disposed at the position adjacent to the fuel injection valve 91 as above-mentioned, it is possible to reduce the length of the fuel supply passage 94 connecting the fuel injection valve 91 and the pressure regulating valve 97 to each other, and to prevent the fuel flowing through the fuel supply passage 94 from

being heated to a high temperature. [0054]
In Figs. 12 to 14, the fuel tank 34A is comprised of a lower tank half 110 and an upper tank half 111 coupled to each other, and a flange portion 112 bulging outwards is integrally formed on the entire circumference of a connection portion between both the tank halves 110 and 111. The fuel tank 34A is supported by both the rear frames 23... of the vehicle body frame 20. The rear frames 23... are provided with stays 113.. far supporting a. front portion of the fuel tank 34A, and support bosses 114... for supporting a rear portion of the fuel tank 34A. The
flange portion 112 mounted on the stays 113... is fastened to the stays 113... by bolts 115... and welded nuts 116..., and the flange portion 112 mounted on the support bosses
114... is fastened to the support bosses 114... by bolts 117
[0055]
Meanwhile, the fuel tank 34A is disposed on the upper side of the rear wheel WR, and a bottom portion of the fuel tank 34A, i.e., a bottom portion of the lower tank half 110 is so formed that its central portion in the left-right direction is bulged upwards, so as to obviate interference with the rear wheel WR. Namely, the

fuel tank 34A is so formed that both side portions 34L and 34R in the left-right direction thereof are deeper than a central portion 34C thereof. [0056]
Referring to Fig. 15 also, a fuel pump 118 is contained in the fuel tank 34, and the fuel pump 118 is attached to an upper wall of he fuel tank 34A, i.e., to the upper tank half 111. [0057]
A flat pump mount portion 119 recessed downwards is provided at a front portion of the upper wall on one of the left and right sides (in this embodiment, a left side portion 34L) of the fuel tank 34A, whereas a hose layout portion 12 0 inclined forwardly downwards is provided at a front portion of the upper wall on the other of the left and right sides (in this embodiment, a right side portion 34R) of the fuel tank 34A. [0058]
The pump mount portion 119 is provided with, for example, an elliptic insertion hole 121 for inserting the fuel pump 118 into the fuel tank 34A. Namely, the fuel pump 118 is laid out on one of the left and right sides (in this embodiment, the left side portion 34L) of the fuel tank 34A.

[0059]
A filter (not shown) is connected to a lower portion of the fuel pump 118, a filter chamber 122 for covering the filter is supported by the lower portion of the fuel pump 118 so as to maintain a predetermined liquid surface level in the filter chamber 122, and a float 123 for detecting the fuel liquid surface in the fuel tank 34A is supported by the fuel pump 118.
[0060]
An elliptically shaped mount plate 124 is welded to the upper surface of the pump mount portion 119 so as to surround the insertion hole 121. The mount plate 124 comprises a plurality of, for example six, lower-level
portions 124a... to be welded to the pump mount portion 119, and a plurality of, for example six, higher-level
portions 124b-•• raised in a trapezoid shape, which are alternately arranged in connection in the circumferential direction, and the lower-level portions 124a... are welded to the upper surface of the pump mount portion 119. [0061]
Referring to Figs. 16 and 17 also, bolts 125... are welded to the lower surfaces of the higher-level portions 124b... so as to project upwards from the higher-level portions 124b... The bolts 125... are passed through an

outer peripheral portion of an elliptic flat plate-like lid plate 126 provided at the upper end of the fuel pump 118 so as to close the insertion hole 121 from the upper side, and nuts 127... screw-engaged with the bolts 125... are fastened, whereby the lid plate 126, namely, the fuel pump 118, is mounted to the pump mount portion 119. [0062]
Moreover, a rubber-made gasket 128 is interposed between the pump mount portion 119 and the lid plate 126. The gasket 12 8 is formed in an elliptic shape while having opening portions 129... in which the higher-level portions 124b'" of the mount plate 124 are to be respectively disposed. By fastening the nuts 127... screw-engaged with the bolts 125...the gasket 128 is clamped between the lower-level portions 124a... of the mount plate 124 and the lid plate 126, and is clamped between the pump mount portion 119 and the lid plate 126 on the inside and the outside of the mount plate 124. [0063]
A discharge pipe 130 bent into a roughly L-shaped form is connected to the upper end of the fuel pump 118, and the fuel pump 118 discharges the fuel through the discharge pipe 130. A return pipe 131 penetrating through the lid plate 126 in a liquid-tight manner and extended
3 4

on a lateral side of the fuel pump 118 to a lower portion of the inside of the fuel tank 34A is attached to the lid plate 126, and the return pipe 131 is bent into a roughly L-shaped form on the upper side of the lid plate 126 in the same manner as the discharge pipe 130.
[0064]
Moreover, the discharge pipe 13 0 and the return pipe 131 are disposed in parallel to each other while being directed to the right forward side on the upper side of the lid plate 126. The upstream end of a fuel hose 132 is connected to the discharge pipe 130, whereas the downstream end of a return hose 13 3 having its upstream end connected to the return-side connection pipe portion 104 of the pressure regulating valve 97 is connected to the return pipe 131.
[0065]
Meanwhile, a flange portion 112 at the front end of the fuel tank 34A along the pointing direction of the discharge pipe 130 and the return pipe 131, namely, at the right front end of the fuel tank 34A, with the fuel pump 118 disposed at a left front portion thereof, is provided with a cutout 135 for forming a space for passing the fuel hose 132 and the return hose 133 between the fuel tank 34 and the luggage box 35A disposed on the

35

front side of the fuel tank 34A. The fuel hose 132 and the return hose 133 are extended downwards from the discharge pipe 130 and the return pipe 131 through the space over the hose layout portion 120 and through the cutout 13 5, and are bent on the rear side of the luggage box 35A so as to extend to the left side of the luggage box 35A. Namely, the fuel hose 132 and the return hose 133 connected to the discharge pipe 130 and the return pipe 131 are disposed in the state of being bent, on the rear side of the luggage box 35A, into a roughly U-shaped form opened to the left side. [0066]
Thus, on the left side of the luggage box 35A, the fuel hose 132 and the return hose 133 extend forwards, in parallel to each other. The downstream end of the fuel hose 132 is connected to a high-pressure filter 136 supported on a front portion of one of the rear frames 23 by a support member 134 on the front left side of the luggage box 3 5A. The fuel hose 13 7, of which the upstream end is connected to the high-pressure filter 136, is connected to the inlet-side connection pipe 95 in the cap 93 so as to supply the fuel to the fuel injection valve 91. Moreover, the high-pressure filter 136 is supported on the rear frame 2 3 by the support member 134 at such a
36

position as to permit easy maintenance through removal of the main frame top cover 42. [0067]
Thus, the fuel hose 132 and the return hose 133 are connected to the cap 93 and the pressure regulating valve 97. The fuel from the fuel pump 118 is reciprocally circulated to the pressure regulating valve 97 disposed in the vicinity of the fuel injection valve 191. Therefore, it is possible to prevent the temperature of the fuel from rising, even where the engine E is disposed on the lower side of the fuel hose 132 and the return hose 133. [0068]
The pump mount portion 119 and the hose layout portion 120 are covered, from the upper side, with a cover 138 for covering the upper end of the fuel pump 118, the fuel hose 132, and the return hose 133. The cover 138 is fastened to a pair of support members 139, 139 fixed to the lid plate 126 of the fuel pump 118. Namely, the cover 138 is attached to the lid plate 126 through the support members 139, 139. [0069]
The support members 13 9, 13 9 are disposed on opposite sides, with the insertion hole 119 of the fuel
37

tank 34A therebetween. The support members 13 9, 13 9 are fastened to the lid plate 126 of the fuel pump 118 by two pairs of bolts 125"' and nuts 127... of the six pairs of bolts 125... and nuts 127... for fastening the lid plate 126 to the mount plate 124, and are so formed as to be raised upwards from the lid plate 126.
[0070]
Moreover, welded nuts 140, 140 are attached to the inside surfaces of upper portions of the support members 139, 139, and screw members 141, 141 passed through the cover 138 mounted on the support members 139, 139 and through the support members 13 9, 13 9 are screw-engaged with the welded nuts 140, 140.
[0071]
In addition, a right end portion of the cover 13 8 disposed at a position spaced from the fuel pump 118 is supported by the stay 113 attached to the right-side rear frame 23 so as to support a right front portion of the fuel tank 34A, and, as shown in Fig. 18, is co-fastened to the stay 113 by the bolt 115 and the welded nut 116, together with the flange portion 112 at a right front portion of the fuel tank 34A.
[0072]
Meanwhile, as shown in Fig. 12, a lower portion of

the luggage box 35A is supported on a support plate 142 disposed between front portions of both the rear frames 23... through a pair of mount members 143...,and, as shown in Fig. 18, left and right top portions of a rear portion of the luggage box 3 5A are supported on front portions of
the stays 113...through mount members 144.... [0073]
The mount members 144... are interposed respectively between support flanges 35a... provided integrally with left and right upper ends of a rear portion of the
luggage box 35A and front portions of the stays 113.... Metallic cylindrical collars 145--- are passed through the support flanges 3 5a..., synthetic resin-made washers 149... making contact with the upper surfaces of the support flanges 35a, and the mount members 1.44-'-. Metallic washers 148"* are placed in contact with the washers 149... and the upper ends of the collars 145. Bolts 147... having engaging and stopping head portions 147a*" to be engaged with the washers 148... are passed through the washers 148 ...and the collars 145..., and, by fastening the bolts 147... screw-engaged with welded nuts 146... attached to the front lower surfaces of the stays 113..., the left and right tops of the rear portion of the luggage box 35A are supported on the stays 113....

[0074]
The front end of the riding seat 3 6 is openably and closably supported on a central upper portion of the front end of the luggage box 35A through a hinge 150, A receiving plate 151 for receiving a rear portion of the riding seat 3 6 when the riding seat 3 6 is closed is provided between rear portions of both the rear frames 23
..., and a pair of elastic members 153... fixed to the lower surface of a bottom plate 36a of the riding seat 36 is placed in contact with the receiving plate 151. Besides, both ends of a grab rail 152 are attached to the receiving plate 151. [0075]
Meanwhile, when the load exerted on the riding seat 3 6 in its closed state is comparatively small, an intermediate portion in the front-rear direction of the riding seat 3 6 would not make contact with the fuel tank 34A. However, when the load is increased to bend the riding seat 36 downwards, seat load receiving positions for receiving the load on the riding seat 36 are set at a plurality of locations in the periphery of the pump mount portion 199, in this embodiment, three locations on an upper wall of the fuel tank 34A. In this case, three elastic members 154A, 154B, 154C fixed to the lower

surface of the bottom plate 36a of the riding seat 36 can make contact with the upper wall of the fuel tank 34A at the seat load receiving positions. Incidentally, a structure may be adopted in which the elastic member 154C is omitted so that the elastic members 154A and 154Bmake contact with the upper wall of the fuel tank 34A at a pair of seat load receiving positions.
[0076]
In addition, a fuel injection port (not shown) for supplying the fuel into the fuel tank 34A is provided in a roughly central portion of the upper wall of the fuel tank 34A, and a fuel injection cap 155 for closing the fuel injection port is detachably attached to the upper wall of the fuel tank 34A.
[0077]
Next, functions of this first embodiment will be described. Since the shield plate 79 for covering at least the throttle drum 4 8 of the throttle body 32 from the front side is provided as one body with the cleaner case 70 of the air cleaner 33, it is possible to prevent water or mud splashed by the front wheel WR from being sprinkled on the throttle drum 48, while obviating an increase in the number of component parts.
[0078]

In addition, since the control unit 53 for controlling the operation of the fuel injection valve 91 for supplying the fuel to the engine E is attached to the body 47 of the throttle body 32 and the control unit 53 is also covered with the shield plate 79 from the front side, it is possible to enhance the waterproof and mud-proof performances of the control unit 53.
[0079]
Further, since the throttle drum guard 161 for covering the throttle drum 4 8 of the throttle body 32 from a lateral side (in this embodiment, the left side) is attached to the cleaner case 70 of the air cleaner 33, it is possible to prevent water or mud from being sprinkled onto the throttle drum 48 from a lateral side of the throttle body 32.
[0080]
Moreover, since the shield plate 79 is provided with the operating opening portion 80 at a position corresponding to the fixing band 77 for connecting to the throttle body 32 the connecting tube 76 for leading cleaned air from the air cleaner 33 and the cover plate 81 for making the operating opening portion 80 openable and closable is attached to the shield plate 79, it can be made easy, notwithstanding the presence of the shield

plate 79, to insert fingers from the front side through the operating opening portion 80 to hold the fixing band 77 and fasten and unfasten the fixing band 77 from a lateral side of the shield plate 79, and it is possible to enhance workability at the time of maintenance and at the time of assembly. [0081]
In addition, since the pump mount portion 119 for mounting the fuel pump 118 to be contained in the fuel tank 34A is provided at the upper wall of the fuel tank 34A in the state of being recessed downwards and the pump mount portion 119 is covered with the cover 138 from the upper side, it is possible to obviate interference with the riding seat 36 and to increase the degree of freedom in setting the height of the riding seat 36, even where connection portions of the fuel hose 132, the return hose 13 3 and the like in relation to the fuel pump 118 are disposed on or over the pump mount portion 119. Moreover, since the pump mount portion 119 is covered with the. cover 3 6 from the upper side, when the riding seat 3 6 is opened for supplying the fuel into the fuel tank 34A or the like purpose it is possible to securely prevent erroneous contact with the above-mentioned connection portions, to protect the connection portions for

connection to the fuel pump 118, to prevent the connection portions from being exposed, and to thereby obtain an excellent appearance. [0082]
Besides, since the lid plate 126 provided at the upper end of the fuel pump 118 so as to close from above the insertion hole 121 provided in the pump mount portion 119 for inserting the fuel pump 118 into the fuel tank 34A is attached to the pump mount portion 119 and the cover 138 is attached to the lid plate 126 through the support members 139, 139, it is unnecessary to provide a special member for fixing the cover 13 8 to the side of the fuel tank 34A, and it is thereby possible to reduce the number of component parts. [0083]
Since the right front portion of the cover 13 8 spaced from the fuel pump 118 is co-fastened, together with the fuel tank 34A, to the stays 113 provided on the rear frames 23 of the vehicle body frame 20 so as to support the fuel tank 34A, it is unnecessary to provide a component part for exclusive use for mounting the cover 138, and it is possible to contrive a reduction in the number of component parts and to firmly support the cover 138.

[0084]
In addition, since the pump mount portion 119 and the fuel pump 118 are disposed at a front portion on one of the left and right sides (in this embodiment, the left side portion 34L) of the fuel tank 34A disposed on the upper side of the rear wheel WR, the fuel pump 118 can be disposed at a deep position in the fuel tank 34A. Namely, the central portion 34C in the left-right direction of the fuel tank 34A becomes shallow due to the arrangement of" the fuel tank 34A on the upper side of the rear wheel WR, and the arrangement of the fuel pump 118 on one of the left and right sides of the fuel tank 34A makes it possible to dispose the fuel pump 118 at a deep position in the fuel tank 34A.
[0085] Besides, the front end portion on the other of the left and right sides (in this embodiment, the right side portion 34R) of the fuel tank 34A is provided with the cutout 135 through which the fuel hose 132 and the return hose 133 extended from the side of the fuel pump 118 are passed between the fuel tank 34A and the rear portion of the luggage box 35A disposed on the front side of the fuel tank 34A, and the fuel hose 132 and the return hose 133 are disposed in the state of being bent in a roughly

U-shaped form opened on one of the left and right sides (in this embodiment, the left side) on the rear side of the luggage box 35A. This ensures that, in spite of the presence of the luggage box 35A on the front side of the fuel tank 34A, the fuel hose 132 and the return hose 133 are bent moderately instead of being bent sharply, and the fuel hose 132 and the return hose 133 can be laid out smoothly.
[0086]
Furthermore, the seat load receiving positions making it possible to bear the riding seat 3 6 on the upper wall of the fuel tank 34A are set at a plurality of locations in the periphery of the pump mount portion 119, and the load on the riding seat 3 6 can be borne on the upper wall of the fuel tank 34A at the plurality of locations in the periphery of the pump mount portion 119 even when the riding seat 3 6 sinks under the action of a large load. Therefore, it is possible to restrain deformation of the riding seat 36, and to prevent the load exerted from the side of the riding seat 36 from acting on the cover 138.
[0087]
Fig. 19 illustrates a second embodiment of the present invention. As shown, a structure may be adopted
45

in which a pump mount portion 119 and a fuel pump 118 are disposed at a front portion of one of the left and right sides (in this embodiment, the left side) of a fuel tank 34B, and a rear end portion on the other of the left and right sides (in this embodiment, the right side) of the luggage box 35B disposed on the front side of the fuel tank 34B is provided with a cutout 157 for passing hoses 132, 13 3 extended from the side of the fuel pump 118 into a space between a front portion of the fuel tank 34B and a rear portion of the luggage box 3 5B.
[0088]
According to the second embodiment, also, the same effects as those of the first embodiment can be obtained.
[0089]
Fig. 20 illustrates a third embodiment of the present invention, in which the upper end of a fuel pump 118 contained in a fuel tank 34C disposed on the front side of a luggage box 3 5C is mounted to a pump mount portion 119' provided in a rear upper wall of a central portion in the left-right direction of the fuel tank 34C, and the pump mount portion 119' is covered with a cover 13 8' from the upper side.
[0090]
Moreover, a front end portion on one side in the

left-right direction of the luggage box 3 5C is provided with a cutout 158 for passing a fuel hose 132 and a return hose 133 extended from the side of the fuel pump 118 into a space between the front end portion of the luggage box 35C and a rear portion of the fuel tank 34C, and the fuel hose 132 and the return hose 133 are disposed in the state of being bent into a roughly U-shaped form opened on the other side in the left-right direction (in this embodiment, the right side) on the rear side of the fuel tank 34C.
[0091]
While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design modifications are possible without departing from the invention as set forth in the claims.
[0092]
[Effects of the Invention]
As described above, according to the invention as set forth in claim 1, even where the connection portion for connection to the fuel pump is disposed on the pump mount portion, it is possible to prevent interference with the riding seat, and to increase the degree of freedom in setting the height of the riding seat.

Moreover, it is possible to protect the connection portion for connection to the fuel pump when the riding seat is opened, and to obtain an excellent appearance. [0093]
In addition, according to the invention as set forth in claim 2, it is possible to eliminate the need for a special member for fixing the cover to the fuel tank side, and to contrive a reduction in the number of component parts. [0094]
According to the invention as set forth in claim 3, it is possible to eliminate the need for a component part for exclusive use for mounting the cover, to thereby contrive a reduction in the number of component parts, and to firmly support the cover. [0095]
According to the invention as set forth in claim 4, it is possible to dispose the fuel pump at a deep position in the fuel tank, and to smoothly lay out the hoses. [0096]
Furthermore, according to the invention as set forth in claim 5, it is possible to restrain deformation of the riding seat, and to prevent the load exerted from
the riding seat side from acting on the cover.

■
[What is Claimed is]
[Claim 1] A fuel system layout structure in a motorcycle comprising a fuel tank (34A, 3 4B; 34C) mounted on a vehicle body frame (20), and a fuel pump (118) attached to an upper wall of said fuel tank (34A to 34C), said fuel pump (118) being contained in said fuel tank
(34A to 34C), and the upper side of said fuel tank (34A to 34C) being covered with a riding seat (36), wherein said fuel pump (118) is mounted to a pump mount portion
(119, 119') provided in said upper wall of said fuel tank
(34A to 34C) in the state of being recessed downwards, and said pump mount portion (119, 119') is covered with a cover (13 8, 138') from the upper side.
[Claim 2] A fuel system layout structure in a motorcycle as set forth in claim 1, wherein said pump mount portion (119, 119') is provided with an insertion hole (121) for inserting said fuel pump (118) into said fuel tank (34A to 34C), a lid plate (126) provided at the upper end of said fuel pump (118) so as to close said insertion hole (121) from the upper side is attached to said pump mount portion (119, 119'), and said cover (138,
51

138') is attached to said lid plate (126).
[Claim 3] A fuel system layout structure in a motorcycle as set forth in claim 1 or 2, wherein at a position spaced from said fuel pump (118), said cover (138) is attached to a stay (113) provided on said vehicle body frame (20) in the state of supporting said fuel tank (34A to 34C).
[Claim 4] A fuel system layout structure in a motorcycle as set forth in any of claims 1 to 3, wherein a luggage box (3SA, 35B) covered with said riding seat (36) is disposed on the front side of said fuel tank (34A, 34B) disposed on the upper side of a rear wheel (WR), said pump mount portion (119) and said fuel pump (118) are disposed at a front portion on One of the left and right sides of said fuel tank (34A, 34B), either a front end portion on the other of the left and right sides of said fuel tank (34A, 34B) or a rear end portion on the other of the left and right sides of said luggage box (35A, 35B) is provided with a cutout (135, 157) for passing hoses (132, 133) extended from the side of said fuel pump (118) into a space between a front portion of said fuel tank (34A, 34B) and a rear portion of said luggage box (35A, 35B), and said hoses (132, 133) are disposed in the state of being bent in a roughly U-shaped

form opened on one side in the left-right direction on the rear side of said luggage box (35A, 35B).
[Claim 5] A fuel system layout structure in a motorcycle as set forth in any of claims 1 to 4, wherein seat load receiving positions for making it possible to receive said riding seat (36) are set on the upper wall of said fuel tank (34A to 34C) at a plurality of locations in the periphery of said pump mount portion (119, 119' ) .

6. A fuel system layout structure in a motorcycle substantially as
hereinbefore described with reference to the accompanying drawings.
Dated this 17th day of October, 2003.